Release Notes

https://github.com/npgsql/Npgsql/releases/tag/v2.2.0-beta1

Major highlights
Visual Studio DDEX support

Kenji Uno added support for DDEX. Now you can use Npgsql with Visual Studio data designer. This is a missing feature a lot of our users requested in the past. Kenji added a tutorial about how to use Npgsql with DDEX. You can find it here: https://github.com/npgsql/Npgsql/wiki/Visual-Studio-Design-Time-Support---DDEX-Provider#install-npgsqlddexprovidervsix
Entity Framework
David Karlaš added support for EFMigration and Database creation in EF6+

Now it is possible to start Code First projects without needing to create a database upfront. EntityFramework and Npgsql will take care of it.
Emil Lenngren added support for a lot of missing features of EntityFramework.

A list containing fixes from David and Emil as well as others for EntityFramework can be seen here: https://github.com/npgsql/Npgsql/issues?direction=desc&labels=entity+framework&milestone=2&page=1&sort=created&state=closed
SSLStream support

In this release, SSLStream is on by default.
If you want to use Mono.Security, you will need to use the following line in your code:

NpgsqlConnection.UseSslStream = false;

Note that in future releases, this option may not be available anymore as we are removing the dependency on Mono.Security assembly. Let us know in the forums if you have any problem with ssl when using SSLStream. This will help us check if we will be able to remove Mono.Security assembly.
Added support for JSON, JSONB and HSTORE datatypes

Shay added support for those datatypes.
Added GSSAPI support on Windows

Brian Crowell added support for GSSAPI on windows. [#170]
Removed support for protocol 2

Postgresql versions which use only protocol 2 are very old and don't receive support from postgresql group anymore. By removing this support, we removed a lot of code and can focus on functionalities provided by protocol 3.
Removed support for Postgresql 8.3 and below

In this thread, https://groups.google.com/forum/#!topic/npgsql-dev/omQ40Eq0HoA, we talked about making Npgsql support the officially supported postgresql versions. This means end of support for postgresql 8.3 and below in the Npgsql 2.2 and up. If you still need support for 7.x, please, use 2.0.x versions.